Chair hinge construction



June 8, 1937. T. w. LEWIS CHAIR HINGE CONSTRUCTION Filed July 6, 1956 INVENTOR.

ATTORNEY.

Patented June 8, 1937 UNITED AENT OFFIQE CHAIR HINGE CONSTRUCTION Application July 6, 1936, Serial No. 89,202

2 Claims.

My invention relates particularly to a hinge construction for mounting a back rest to an uprightsupport or chair post so that the back rest may assume various positions suitable to the comfort of the user. The application of this invention, though not confined thereto, is primarily designed for typewriter chairs. Prior inventions have been directed toward back rest attachments. However the inventor believes that this invention has certain advantages surpassing others now in use. The mechanism allows the back rest to fit the spine of the user of the chair and to remain in a supporting position in either the forward or backward sitting posture of the occupant thereby combating fatigue and weariness accompanying sitting in a chair for long hours.

One of the principal objects of my invention is to provide a new and improved hinge construction of simplified design for a back rest which will permit the back rest to adjust itself on slight pressure to the desired position of the user and then to return to a. predetermined position after its being so used, and without noise or manual adjustment.

An important object of my invention is to provide a sturdy hinge or resilient attachment for a back rest without exposed elements which are prone to catch dust and other foreign matters.

Another object of my invention is to provide a hinge construction for a back rest consisting of a minimum number of parts all cheaply manufactured without expensive machining.

A further object of my invention is to provide a hinge construction for a back rest of stream line design lending itself artistically as well as practically with the lines of the furniture.

Numerous other objects and advantages: will become apparent on becoming familiar with'the details of the invention through examination of the accompanying drawing.

Figure 1 is a View of section AA of Figure 2 with ear members extending outward before being bent back on chair post.

Figure 2 is a section of side elevation of the upright support member or chair post, the hinge construction and the back rest.

Figure 3 is a detail perspective of the spring holder with ear members extending outward before being bent back on chair post.

Figure 4 is a detail perspective of the T-shape rocker arm member.

Figure 5 is a detail perspective of spring member inserted in spring holder.

Upright member I may be the upper portion of any back rest support and is hereinafter referred to as chair post, with the end rounded and the edge smoothed off to provide a nearly vertical plane surface 2. Spring holder 3 consists of a. hollow metal casing 4 with side plates 5. The ears '6 are stamped out of the casing 4, as shown more particularly in Figure 3, and holes 1 are countersunk so that on bending the ears 6 back around the chair post I, as shown in Figure 2, the holder may be permanently affixed to the chair post by screws 8. Spring stops 9, which are elongations of the casing 4 at either end, are turned in at right angles forming thestops for the inserted spring members M. A rectangular aperture I is cut in the casing 4 to permit the insertion of the T-shape rocker arm ll, which is slightly narrower in width than casing 3. Holes [2 are cut incorresponding positions in the side plates so that the rocker bolt or pivot pin 13 maybe inserted and held in a. fixed position in spring holder 3, with rocker arm ll pivoting thereon.

Spring members It, two in number, may be fashioned from flat spring steel and bent to fit within the spring holder 3. The lips [5 on each spring member are bent to rest against the spring stops 9. The longer legs E6 of the spring members are made to press under a slight tension on either side of the rocker arm I I when inserted, so that the pressure of each spring tends to hold the plane of rocker arm H in a position at right angles with the plane of the surface 2 of chair post I.

As rocker arm H is pivoted about the rocker bolt IS, the tension of leg I6 of one of the spring members i l will be increased. However spring stop 9 will prevent the spring member 14 from rotating .or getting out of position, and on the releasing of the pressure on rocker arm Ii the spring member under tension will tend to pivot the arm into neutral position. Leg iii of the corresponding spring will tend to counteract the force of the other spring member so that there will be little or no vibration of the rocker arm before assuming the neutral position.

Rocker arm II is T-shape with flanged portions 19 and holes 20 cut therein. As shown in Figure 2, the flanged portions l9 may be slightly Figure 2 shows the spring holder 3 permanently fixed to the chair post I with two spring members M in position and legs i6 resting fiush with the surfaces of the rocker arm I l to mutually urge the arm into neutral position. It is apparent that any pressure on the back rest I! will tend to pivot the rocker arm II about its pivot pin l3, resulting in either of the two spring members l4 being placed in tension. Should the chair post I which may be resiliently pivotally mounted be in a rearward position and the occupant of the chair shift forwardly, the chair post will urge the back rest against the back of the occupant. The back rest will rotate to a new position, and the pressure will be shifted from one portion of the back rest to another. The spring members will allow the back rest to pivot easily so that it constantly tends to press comfortably against the back of the occupant.

As is readily apparent, this hinge construction may be made with a minimum number of parts all cheaply manufactured; To provide against any possible noise in the operation of the hinge, a graphite lubricant can be spread over the surface of the spring members coming in contact with other members, and as these parts are all covered this may be done without danger of the chair occupant brushing the parts.

It can be readily seen that the parts are enclosed in the spring holder with a minimum amount of exposed surface for dust or other foreign particles to collect upon. The hinge construction is so simplified in design as to appear like the rounded off portion of the upper end of the chair post in a stream line eifect. The hinge is compact and neat in appearance and such design lends to the beauty and perfection of the furniture as well as to its utility. There is no ugly projecting end of the upright support member or chair post nor exposed springs and the like.

It should be further noted that excepting the spring member, the parts of the hinge construction may be manufactured of composite material or metal instead of steel. It is within the purview of the invention to utilize parts which may be molded and have substantial durability.

The invention has been described in detail. However the description has been made to illustrate the invention rather than to limit it, and various departures as to the shape and construction of the parts may be indulged in without departing from the spirit and scope of the invention.

What I claim is:

1. In a hinge construction for pivotally connecting a back rest of a chair to a chair post, the combination of a hollow semi-cylindricallyshaped spring holder having inwardly directed shoulders at its diametrically opposed edges and an elongated slot intermediate the shoulders, a T-shape rocker arm adapted to be permanently attached to the back rest whose longer arm is inserted through the slot and pivotally attached to said holder, resilient plate members confined under tension within said holder and having flanges on their opposite ends engaging said shoulders, and abutting said rocker arm on either side, tending to mutually urge the said rocker arm into a predetermined or neutral position. v

2. In a chair back assembly, the combination of a chair post, a back rest, a slotted semi-cylindrically-shaped hollow holder member, with inwardly directed shoulders at its diametrically opposed edges, fastened along its diameter to the upper end of the chair post with the plane of the slot in nearly a vertical plane, a T-shaped rocker arm adapted to be attached to the back rest having an elongated leg which is inserted into the said slot to the greater part of its depth, and pivotally attached to the sides of the said holder, adjacent to the slot, resilient members within the said holder abutting said rocker leg and engaging said shoulders on either side tending to mutually urge the said rocker arm into a plane at right angles with the plane of the upper end of the chair post.

THOMAS W. LEWIS. 

